Western Digital's inevitable Thunderbolt offering is missing solid state guts—and that hurts it a lot. But what it lacks in speed, it makes up for in capacity. It is an enormous vault, with more space than most humans will ever need.

What Is It?

The Yucca Mountain of external hard drives—6 terabytes of storage in a RAID array, plus a Thunderbolt connection.

Who's it For?

Videographers, and others who need a massive amount of storage, accessible as fast as possible.

Design

It's about as graceful as a big-ass external with two bays can be. But there's a cheap-feeling pop-up plastic top to access the drives themselves.

Using It

Plug it in, save your stuff, repeat. Stop if you reach six terabytes.

The Best Part

The Thunderbolt Duo is speedy, considering the fact that it's using ol' fashioned mechanical drives. Synthetic testing showed the Duo with about the same write speed and half the read speed of the (SSD) Little Big Disk, but a real world test of moving a 19 GB photo library told another tale: about three minutes to copy over, and about eight to copy back to a MacBook Air's SSD.